Sticking micro switch, if you leave it in the failed place for about 30 minites it might free up and go ahead and work. These switches will stick, mostly due to the silicone boot around the pin, the pin gets stuck to the boot and when the pressure is released, the pin does not.

If you find thats the problem graphite lock lube seems to work wonders on these things. (SLKs are famos for the decklid and front bow micros doing the same thing.)